This invention relates to water-soluble polymers. Water-soluble polymers are used in many applications ranging from improved oil recovery, metal working fluid lubrication, and gellants in the food industry. It is known that the production of large amounts of water from oil and gas wells constitutes one of the major expenses in the overall recovery of hydrocarbons from a subterranean reservoir and that some water-soluble polymers reduce such water production. See, for example, Treybig et al. U.S. Pat. No. 6,569,983 and Ahmed et al. U.S. Pat. No. 6,051,670.
It is also well known that polymers and gelled or crosslinked water-soluble polymers have been used to alter the permeability of subterranean formations in order to enhance the effectiveness of water flooding operations. Generally, the polymers are injected into the formation and permeate into the regions having the highest water permeability. It is theorized that the polymer blocks the water permeable zones in the formation, thus reducing the amount of water produced with the oil. Existing polymers, such as polyacrylamides, do reduce water production but they also reduce oil production.
It would be desirable to provide water-soluble polymers that reduce water production but does not affect oil production.